Purpose: Preterm premature rupture of membranes occurs in approximately 2% of all pregnancies and accounts for 20% of perinatal deaths. Complications associated with preterm premature rupture of membranes include preterm labor, maternal and fetal infection and intrauterine death. We hypothesize that a rise in serum Interleukin-6 in patients with preterm premature rupture of membranes without clinical evidence of infection may indicate the onset of intrauterine infection. An elevation in the serum Interleukin-6 levels in these patients may serve as a marker for women with impending intrauterine infection and potential neonatal sepsis. The ability to identify these intrauterine infections early would allow for more prompt initiation of antibiotic therapy and/or delivery, which may result in prevention of adverse neonatal outcome. The study Aims are 1. to examine the relationship between blood Interleukin-6 levels in-patients with preterm premature rupture of membranes and clinical infection, and 2. to determine if elevated serum cytokine levels are predictive of the onset of intrauterine infection prior to clinical symptoms. Methods: Patients entering the Duke University Medical Center prenatal care system will be eligible to enroll in this prospective study. A 5 ml blood sample will be obtained from pregnant patients upon admission to labor and delivery. Patients admitted with preterm premature rupture of membranes will be asked to have daily blood samples drawn. The blood samples will be refrigerated and then centrifuged at 600g for 10 minutes. The serum will be removed and either studied immediately or frozen at -70oC for future evaluation. The fluid analysis will be performed using a specific ELISA technique for the identification of Interleukin-6. Variables for analysis will include gestational age, presence of labor, clinical evidence of infection (including maternal fever, maternal or fetal tachycardia, leukocytosis, and uterine tenderness), maternal blood Interleukin-6 levels, histologic signs of infection present in the placenta after delivery and perinatal outcome. We will correlate maternal Interleukin-6 levels with the onset of labor or clinical signs of infection in-patients being followed with preterm premature rupture of membranes. Results: Thirty two of the thirty five required subjects have been enrolled in the study. Three subjects withdrew from the study leaving 29 subjects available for analysis. Of those subjects available for analysis 74% developed chorioamnionitis by histologic criteria. Maternal serum is currently frozen and will be analyzed at the completion of patient enrollment. Significance: Management of preterm premature rupture of membranes in the absence of labor is often difficult and controversial. Early signs of infection are usually very subtle or absent in most patients. Once an intrauterine infection is present in the setting of preterm premature rupture of membranes, the fetus is at risk of becoming infected. Fetal sepsis may occur resulting in a significant increase in morbidity and mortality. If a rise in Interleukin-6 occurs in the absence of, or prior to the development of clinical symptoms of infection, this would aid physicians in caring for the mothers ad the fetus. Future plans: We plan to complete enrollment in this study.